In the late Qing Dynasty, the policeman Wang Wu (played by Zheng Haonan) was dedicated to arresting imperial criminals for the court. He was called the "Wang Wu of the Big Sword" because of his good use of a big knife. An Xiaoren, the imperial censor of the time, spoke bluntly, impeaching the eunuch Li Lianying for interfering in the government, which angered Cixi. Xi ordered Wu to suppress and kill Ren's family, and Wu to avoid killing Zhongliang by mistake, but he openly disobeyed the order, thus incurring the disaster of exterminating the family. Wu's wife Ao Xue (played by Lan Jieying) was brutally murdered, and Wu Sui and her young son wandered around the world. Sado (played by Yin Yangming), the governor of the imperial court, was ordered to hunt down the five fathers and sons. Although the five and many cherished each other, the two still could not escape a life-and-death battle in the end...